In many industrial manufacturing processes, mechanical fasteners, such as rivets, screws, bolts and similar are used to connect or affix two or more objects together. The installation of such mechanical fasteners is often automated by machines or robots that can install mechanical fasteners much quicker and with a higher precision than a human being.
In some applications, such as aircraft construction, it is necessary to provide the fasteners with a sealant prior to installation. Such a sealant avoids the leakage of air or water through the holes in which the fasteners are installed. It is desirable to apply the sealant to the fasteners immediately before installation to avoid premature curing of the sealant as well as to avoid a contamination of the machine or robot with the sealant while handling the fasteners.
Furthermore, it is desirable that the sealant is applied reliably and in a constant and predictable amount to avoid insufficiently sealed junctures on the one hand and to avoid excess sealant around the juncture on the other hand. This aspect is in particular important in aircraft construction, where leakages may have severe effects, but where excess sealant impairs aerodynamic properties.
From prior art document DE 20 2008 014886 U1 a robot effector is known for installing mechanical fasteners, in particular rivets. In one embodiment the mechanical fasteners are two-piece rivets having a shaft and a complementary hollow counterpart. The shaft may comprise an area for receiving a sealant which may seal an opening in a workpiece if the rivet is installed and may also glue the rivet.